/Engine/Source/Runtime/RHI/Public/DynamicRHI.h
Reads the contents of a texture to an output buffer (non MSAA and MSAA) and returns it as aFColorarray. If the format or texture type is unsupported the OutData array will be size 0
void RHIReadSurfaceData ( [FRHITexture](API\Runtime\RHI\FRHITexture) * Texture, FIntRect Rect, [TArray](API\Runtime\Core\Containers\TArray)< [FColor](API\Runtime\Core\Math\FColor) > & OutData, [FReadSurfaceDataFlags](API\Runtime\RHI\FReadSurfaceDataFlags) InFlags )